The present invention relates to a gas-blast switch.
The invention relates to gas-blast switches, of the type described in DE-C2-2,811,947. The known gas-blast switch has a heating volume which is filled with quenching gas. When the switch is opened, the quenching-gas pressure is rises in proportion to depend the intensity of the current to be cut off, as result of the heat produced by an arc drawn between two separating switch contact pieces. To obtain a quenching-gas pressure which is high enough to blow the arc when comparatively low currents are cut off, it is necessary to prevent the quenching gas from flowing off from the heating volume prematurely. This is done by means of a valve dependent on the position of the moveable contact of the two contact pieces of the switch. Moreover, a further valve is necessary to prevent overloading of the heating volume when comparatively high currents are switched.